50th Anniversary Perspective: The Importance of NMR Spectroscopy to Macromolecular Science

Abstract

An overview is given of the development of NMR spectroscopy during the past 50 years with emphasis on applications in macromolecular science. The unique versatility of the technique, in particular solid-state NMR, being able to elucidate structure and dynamics over wide ranges in space and time is demonstrated. The examples presented illustrate how advanced NMR methods meet the challenges posed by the delicate interplay of structure and dynamics in macromolecular and supramolecular systems, leading to increasing complexity and functionality. An outlook is given on new developments that overcome the limits of NMR due to its inherently low sensitivity. Likewise, the importance of in situ NMR experiments is pointed out, which can better link the information available from NMR to the properties and function of polymer materials.

A Generalized Packing Model for Bulk Crystalline Regioregular Poly(3‐alkylthiophenes) with Extended Side Chains

“…[38] Combining these properties with its unique site selectivity, solid-state NMR gives access to information about local structural details in noncrystalline materials that are not easily achieved using other experimental techniques. [39,40] This relies on the fact that solid-state NMR probes the local environments of the nuclei selectively through short-range nuclear spin interactions, such as dipole-dipole and chemical shift interactions, which are sensitive probes with respect to the local packing arrangements, [41][42][43][44][45][46] hydrogen bonding, [47][48][49] and proton-proton proximities. [50][51][52] To relate the 1 H chemical shifts and distance constraints from solid-state NMR to a specific packing arrangement the application of quantum-chemical calculations at the atomistic level becomes essential.…”

1H PFG‐NMR Diffusion Study on a Sequence‐Defined Macromolecule: Confirming Monodispersity

“…The choice and definition of suitable and reliable methods depends on individual applications. Several analytical techniques are used for characterization of synthetic sequence‐defined polymers, for example, size exclusion chromatography (SEC), electrospray ionization mass spectrometry (ESI‐MS), matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐ToF‐MS), Fourier transform infrared (FT‐IR) spectroscopy, and nuclear magnetic resonance (NMR). Recent studies showed that other promising tools, such as nanopore‐based analytics and electrospray ion beam deposition combined with high‐resolution scanning tunneling microscopy (STM/ES‐IBD) are explored for sequence‐defined polymer analysis .…”

“…A variety of NMR characterization techniques for polymeric systems are established . More recently, an overview of the development of NMR spectroscopy with emphasis on applications in macromolecular science has been reported by Spiess . So far, there have been few reports on pulsed field gradient NMR or diffusion‐ordered spectroscopy (PFG‐NMR/DOSY) study of synthetic sequence‐defined oligomeric macromolecules …”

“…[25][26][27][28] More recently, an overview of the development of NMR spectroscopy with emphasis on applications in macromolecular science has been reported by Spiess. [17] So far, there have been few reports on pulsed field gradient NMR or diffusion-ordered spectroscopy (PFG-NMR/DOSY) study of synthetic sequence-defined oligomeric macromolecules. [29,30] To overcome the challenge in characterization of sequencedefined macromolecules with dispersity close to 1, the diffusion properties of a sequence-defined decamer, which serves as a model oligomer system, were investigated by 1 H PFG-NMR.…”

Exploiting Heterogeneous Time Scale of Dynamics to Enhance 2D HETCOR Solid-State NMR Sensitivity

“…Solid-state NMR spectroscopy is a powerful analytical tool that is widely used for studying molecular structures and dynamics of a variety of solids including membrane proteins, [1][2][3][4][5] multiphase polymers [6][7][8], bone materials, [9][10][11] amyloids [12][13][14][15][16][17], and nanocomposites [18][19][20][21]. The benefits of multidimensional NMR techniques to obtain higher resolution and higher degree of structural and dynamic information have been well utilized in numerous applications, among which 2D homonuclear (HOMCOR) [22][23][24][25] and heteronuclear (HETCOR) [26][27][28][29][30][31] chemical shift correlation experiments are most widely employed and have become indispensable for structural studies of proteins.…”